Robert Burton describes an experiment in his book On Being Certain: Believing You Are Right Even When You Are Not, which everyone with a strong opinion should read. Immediately after the Challenger explosion in 1986, the psychologist Ulric Neisser asked 106 students to describe in writing where they were when they heard, who they were with, how they felt, what their first thoughts were. Two-and-a-half years later, the same students were assembled and asked to answer the same question in writing. The new descriptions were compared with the originals. They didn’t match. People had changed facts about where they were, who they were with, what they felt, what they thought. When confronted with the original essays, people were so attached to their new memories they had trouble believing their old ones. In fact, most refused to revise their memories to match the originals written at the time. What struck Burton was the response of one student: “That’s my handwriting, but that’s not what happened.”

We overestimate how happy we will be on our birthdays, we underestimate how happy we will be on Monday mornings, and we make these mundane but erroneous predictions again and again, despite their regular disconfirmation.

So what are the solutions here?

1) Keep a list of what makes you very happy and very unhappy

Stop trusting your memory. Write things down. Feelings are fleeting. Keep a list of things that make you very happy and very sad.

This trio of studies suggests that when people are deprived of the information that imagination requires and are thus forced to use others as surrogates, they make remarkably accurate predictions about their future feelings, which suggests that the best way to predict our feelings tomorrow is to see how others are feeling today.

Sorry, you’re not a unique snowflake. We’re more similar to others than we are different. Don’t fight this, embrace it. It can be the key to a much happier life:

The irony, of course, is that surrogation is a cheap and effective way to predict one’s future emotions, but because we don’t realise just how similar we all are, we reject this reliable method and rely instead on our imaginations, as flawed and fallible as they may be.

3) Use your brain’s errors to make memories happier

Yes, your brain is imperfect, but it’s often imperfect in the same ways. You can use it’s errors to your advantage.

Daniel Kahneman, Nobel Prize winner and author of Thinking, Fast and Slow, has shown that your brain consistently remembers only two things about an event:

Nobel Prize-winning psychologist Daniel Kahneman and his colleagues have shown that what we remember about the pleasurable quality of our past experiences is almost entirely determined by two things: how the experiences felt when they were at their peak (best or worst), and how they felt when they ended. This “peak-end” rule of Kahneman’s is what we use to summarize the experience, and then we rely on that summary later to remind ourselves of how the experience felt.

So how can you game the system with this information and have happier memories?

Structure events so that the peak is great and the ending is great.

Make sure tomorrow has one thing that will be amazing and that the day ends on a positive note. This is what leads to feeling good about your life in retrospect.

Your brain is not a perfect computer. What you will remember is not the same as what happened.

But you can game it so your memories are better than what happened. And happy memories are one of the secrets to feeling good about your life.